KR101164117B1 - Method of controlling a monitoring operation of a physical downlink channel in wireless communication system - Google Patents

Abstract

The present invention relates to a wireless communication system and a terminal for providing a wireless communication service, and to a base station in an Evolved Universal Mobile Telecommunications System (E-UMTS) or a Long Term Evolution System (LTE). The present invention relates to a method for transmitting and receiving data, and more particularly, to a method for reducing power consumption of the terminal by increasing the time for which the terminal monitors the downlink discontinuously in monitoring the downlink channel of the terminal.

Description

METHOOD OF CONTROLLING A MONITORING OPERATION OF A PHYSICAL DOWNLINK CHANNEL IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a wireless communication system and a terminal for providing a wireless communication service, and to a base station in an Evolved Universal Mobile Telecommunications System (E-UMTS) or a Long Term Evolution System (LTE). The present invention relates to a method for transmitting and receiving data, and more particularly, to a method for reducing power consumption of a terminal by increasing a time for which the terminal discontinuously monitors a downlink channel of the terminal.

1 is a diagram illustrating a network structure of an Evolved Universal Mobile Telecommunications System (E-UMTS), which is a mobile communication system to which the present invention and the present invention are applied.

The E-UMTS system is an evolution from the existing UMTS system and is currently undergoing basic standardization in 3GPP. The E-UMTS system may be referred to as a Long Term Evolution (LTE) system.

E-UMTS networks can be largely divided into E-UTRAN and CN. The E-UTRAN is a UE (hereinafter abbreviated as UE) and a base station (hereinafter abbreviated as eNode B), a serving gateway (abbreviated as S-GW) located at the end of the network and connected to an external network. It consists of a Mobility Management Entity (hereinafter referred to as MME) that manages the mobility of. One or more cells may exist in one eNode B.

2 and 3 illustrate a structure of a radio interface protocol between a terminal and a base station based on the 3GPP radio access network standard. The wireless interface protocol consists of a physical layer, a data link layer, and a network layer horizontally, and vertically a user plane and control for data information transmission. It is divided into a control plane for signal transmission. The protocol layers are based on the lower three layers of the Open System Interconnection (OSI) reference model, which are well known in communication systems. L1 (Layer 1), L2 (Layer 2), and L3 (Layer 3) It can be divided into.

Hereinafter, each layer of the wireless protocol control plane of FIG. 2 and the wireless protocol user plane of FIG. 3 will be described.

The physical layer, which is the first layer, provides an information transfer service to an upper layer by using a physical channel. The physical layer is connected to the upper medium access control layer through a transport channel, and data between the medium access control layer and the physical layer moves through the transport channel. Then, data moves between different physical layers, that is, between physical layers of a transmitting side and a receiving side through a physical channel.

Medium access control (hereinafter referred to as MAC) of the second layer provides a service to a radio link control layer, which is a higher layer, through a logical channel. The radio link control layer (hereinafter referred to as RLC) layer of the second layer supports reliable data transmission. The PDCP layer of the second layer is a header compression that reduces the IP packet header size, which is relatively large and contains unnecessary control information, for efficient transmission in a low bandwidth wireless section when transmitting an IP packet such as IPv4 or IPv6. Compression) function. The PDCP layer is also used to perform encryption of C-plane data, for example RRC messages. PDCP also performs encryption of U-plane data.

The radio resource control layer (hereinafter abbreviated as RRC) layer located at the bottom of the third layer is defined only in the control plane, and the configuration and resetting of radio bearers (abbreviated as RB) are performed. It is responsible for the control of logical channels, transport channels and physical channels in relation to configuration and release. In this case, RB means a service provided by the second layer for data transmission between the terminal and the E-UTRAN.

According to the conventional radio resource allocation request scheme, the terminal must continuously monitor the downlink channel after requesting the radio resource allocation to the base station until the radio resource is allocated from the base station. However, in general, since the terminal does not receive a radio resource immediately after transmitting the radio resource request to the base station, it is unnecessary operation for the terminal to continuously monitor the downlink channel. It causes unnecessary power consumption of the terminal.

Accordingly, the present invention is to provide a method for maximizing the power efficiency of the terminal by excluding unnecessary monitoring intervals during the operation of the terminal to monitor the downlink channel when the terminal requests allocation of radio resources to the base station.

In order to solve the above problems of the present invention, a method for controlling a monitoring operation of a physical downlink channel in a wireless communication system, the method for allocating at least one radio resource for uplink data transmission Triggering signaling; Determining whether the triggered signaling has been transmitted to a network; And selectively performing the monitoring operation of the physical downlink channel based on the determination step.

Preferably, the monitoring operation is performed if it is determined that the triggered signaling is transmitted to the network.

Preferably, the monitoring operation is not performed if it is determined that the triggered signaling is not transmitted to the network.

Preferably, the signaling is characterized in that it is transmitted to the network via a Physical Uplink Control Channel (PUCCH).

Preferably, the signaling is characterized in that the scheduling request (SR) signaling.

Preferably, the physical downlink channel is characterized in that the physical downlink control channel (PDCCH).

Preferably, the signaling is characterized in that associated with a scheduling request procedure (SR procedure).

The present invention provides a method of excluding unnecessary operation of continuously monitoring the downlink channel by the terminal in the process of allocating radio resources from the base station, thereby preventing the unnecessary power loss of the terminal.

1 is a network structure of an E-UMTS, which is a mobile communication system to which the present invention and the present invention are applied.
2 is a control plane structure of a radio interface protocol between a UE and a UTRAN (UMTS Terrestrial Radio Access Network) based on the 3GPP radio access network standard.
3 is a user plane structure of a radio interface protocol between a UE and a UTRAN (UMTS Terrestrial Radio Access Network) based on the 3GPP radio access network standard.
4 is an exemplary diagram illustrating a scheduling fairy process using a Dedicated Scheduling Request (D-SR) channel.
5 is an exemplary diagram illustrating a process in which a terminal is allocated a radio resource after a BSR (Buffer Status Report) is triggered and a scheduling request (SR) is triggered.
6 is an exemplary diagram illustrating a process in which a terminal is allocated a radio resource after a scheduling request (SR) is triggered by triggering a buffer status report (BSR) according to the present invention.

The present invention is applied to 3GPP communication technology, in particular UMTS (Universal Mobile Telecommunications System) system, communication device and communication method. However, the present invention is not limited thereto and may be applied to all wired and wireless communication to which the technical spirit of the present invention can be applied.

The basic concept of the present invention is a method of controlling a monitoring operation of a physical downlink channel in a wireless communication system, and includes signaling for allocating at least one radio resource for uplink data transmission. Triggering; Determining whether the triggered signaling has been transmitted to a network; And selectively performing the monitoring operation of the physical downlink channel based on the determination step, and suggest a method of controlling the monitoring operation of the physical downlink channel in the wireless communication system. The present invention proposes a wireless mobile communication terminal.

Hereinafter, the configuration and operation of the embodiments according to the present invention will be described with reference to the accompanying drawings.

In general, in the LTE system, in order to use radio resources efficiently, the base station needs to know how much data to transmit for each user (terminal). In the case of downlink data, this downlink data is transferred from an access gateway to the base station. Thus, the base station knows how much data should be delivered to the downlink to each user. On the contrary, in the case of data on the uplink, the base station cannot know how much uplink radio resources each terminal needs unless the terminal directly informs the base station of information about data to be transmitted on the uplink. Therefore, in order for the base station to properly allocate uplink radio resources to the terminal, each terminal should provide the base station with information necessary for the base station to schedule radio resources.

To this end, when there is data to be transmitted by the terminal, it notifies the base station, and the base station transmits a radio resource allocation message (Resource Allocation Message) to the terminal based on this information. In the above process, that is, when the terminal informs the base station when there is data to be transmitted, the terminal informs the base station of the amount of data accumulated in its buffer. This is called Buffer Status Report (BSR).

However, the buffer status information is generated in the form of a MAC Control Element and included in a MAC PDU and transmitted from the terminal to the base station. That is, uplink radio resources are required to transmit buffer status information. This means that uplink radio resource allocation request information for transmitting buffer status information should be transmitted. That is, when the buffer state information is generated, if there is an allocated uplink radio resource, the terminal may immediately transmit the buffer state information by using the uplink radio resource. However, if the buffer state information is generated, if there is no allocated uplink radio resource, the terminal performs a resource allocation request (SR) process.

Here, the SR process is largely classified into two methods, a method using a dedicated scheduling request (D-SR) channel set to a physical uplink control channel (PUCCH) resource, and a random access channel (RACH) process. There is a way. That is, when the SR process is triggered, the terminal sends a radio resource allocation request using the D-SR channel, if the D-SR channel is allocated, and if the D-SR channel is not allocated, Start the RACH process. Here, if the SR process uses the D-SR channel, the resource request allocation signal is transmitted in the uplink direction through the D-SR channel. The SR process continues until the terminal is allocated UL-SCH resources.

4 is an exemplary diagram illustrating a scheduling fairy process using a Dedicated Scheduling Request (D-SR) channel.

As shown in FIG. 4, the base station allocates a D-SR channel resource to the terminal, which is determined at regular intervals. If there is data to be transmitted in the uplink direction and the radio resource is not allocated, the terminal sets and transmits the D-SR channel. If there is no data to transmit in the upward direction, the terminal does not use the D-SR channel. . Subsequently, the base station receiving the D-SR channel from the terminal determines resource allocation according to a scheduling algorithm, and assigns an uplink radio resource to be allocated to the terminal through a physical downlink control channel (PDCCH). You can let them know.

The DRX will be described below. In general, the DRX refers to methods for allowing a base station to perform radio resources only at a specific time in allocating radio resources to the terminal. In other words, if the terminal and the base station have a predetermined time for allocating or allocating radio resources, the terminal may stop monitoring of a downlink channel or the like at a time other than that time. Reduce waste

The DRX stands for Discontinuous reception, and refers to an operation of when the base station sends information related to the allocation of radio resources to the terminal while the base station and the terminal communicate with each other. That is, the terminal always monitors the downlink channel, in particular the physical downlink control channel (PDCCH) brings the power consumption of the terminal. Therefore, to solve this problem, the base station and the base station according to a predetermined predetermined rule, the base station to send radio resource allocation information to the terminal through the PDCCH only at a specific time. Accordingly, since the UE only needs to monitor the PDCCH at the specific time, power consumption can be reduced.

In general, in the LTE system, the DRX method uses two DRX cycles. The first is a long DRX cycle and the second is a short DRX cycle. This allows the long DRX cycle and the short DRX cycle of the short period to be appropriately used according to the data transmission situation, thereby minimizing the transmission delay of the data and maximizing battery saving of the terminal. In general, SFN stands for System Frame Number, which is composed of 10 sub-frames, and becomes a reference of absolute time in one cell. Next, the active time will be described. The activation time means a time at which the UE wakes up and monitors a downlink channel, for example, the PDCCH. In addition, the UE does not need to monitor the PDCCH at a time after the activation time.

Here, the active time may include the following times.

1.On-Duration Timer, or DRX Inactivity Timer, or DRX Retransmission Timer or Contention Resolution Timer

2. The time when the scheduling request process is performed

3. The time at which a radio resource allocation message for retransmission may be transmitted in connection with the upward transmission.

4. Time from receipt of RACH message (MSG) 2 until reception of C-RNTI or Temporary C-RNTI indicating allocation of radio resource indicating new transmission (Initial Transmission).

When the DRX function is configured, the UE performs the following operation every transmission time interval (TTI) (sub-frame).

When Short DRX cycle is used, the value of [(SFN * 10) + sub-frame number] divided by Short DRX cycle value is equal to DRX start Offset value, or when Long DRX cycle is used, [(SFN * 10) + sub-frame number] SFN * 10) + sub-frame number], when the remaining value divided by the Long DRX cycle value is equal to the DRX start Offset value, the On Duration timer is operated.

If the HARQ round trip time (RTT) timer expires in this sub-frame and the corresponding HARQ buffer is not successfully decoded, the DRX retransmission timer is started.

When the DRX command (DRX MAC Control Element) is received, the On-Duration timer is stopped. Or stop the Inactivity Timer.

If Short DRX Cycle is set when Inactivity Timer expires or DRX command is received, run DRX Short Cycle Timer and use Short DRX cycle. If the Short DRX cycle is not set when the DRX command is received, the Long DRX Cycle is used.

If the DRX short cycle timer expires, the Long DRX Cycle is used.

During the active time, the UE monitors a physical downlink control channel (PDCCH) in exceptional cases (except for uplink transmission or measurement gap of a half-duplex terminal).

If a DL assignment is received or a sub-frame having a configured DL assignment is started, the HARQ RTT timer is started and the DRX Retransmission Timer for the process is stopped.

If the PDCCH indicates a new transmission, the DRX Inactivity timer is driven or restarted.

The following describes a radio resource allocation request method. When the terminal requests allocation of radio resources to a base station through a dedicated scheduling request (D-SR) channel, the terminal continuously transmits the radio resource allocation request through the D-SR channel until the radio resources are allocated. Downstream channels should be monitored. However, in general, as soon as a terminal performs a radio resource allocation request transmission through the D-SR channel, the terminal is not allocated an uplink radio resource.

As shown in FIG. 4, when the UE uses the D-SR channel, that is, at 1, the actual UE is allocated radio resources, that is, at time 4, the propagation delay of radio waves and the processing time of the BS are determined. In general, it takes about 7 ~ 8ms. Therefore, as soon as the terminal transmits a radio resource allocation request through the D-SR channel, the terminal cannot receive a radio resource allocation message from the base station. However, in general, the terminal continuously monitors the downlink channel, which causes power consumption of the terminal.

5 is an exemplary diagram illustrating a process in which a terminal is allocated a radio resource after a BSR (Buffer Status Report) is triggered and a scheduling request (SR) is triggered.

As shown in FIG. 5, the process in which the terminal allocates the radio resource may be divided into a total of four sections.

First, the first section is a period from when a scheduling request (SR) is triggered to when a scheduling request (SR) is first transmitted on a physical uplink control channel (PUCCH). to be. In general, the first interval is related to how often resources of the PUCCH are allocated for the SR request transmission. In FIG. 5, it is assumed that the PUCCH resources are allocated to 0 ms, 20 ms, and 40 ms. If the SR is triggered near 2 ms, since the actual SR is transmitted through the PUCCH, 20 ms, the terminal is no longer between 2 ms and 20 ms. Can't take action. However, in general, the UE monitors the downlink channel (eg, Physical Downlink Control Channel (PDCCH)) during this period.

The second section is a section from after the SR is transmitted on the PUCCH to a time point where the terminal can first receive a UL Grant from a base station (for example, an eNB). In general, the second section is associated with an up / down round trip time (RTT) and a minimum processing time of the base station. That is, when the SR is actually transmitted through the PUCCH, it is transmitted to the radio end, so a delay occurs, and the base station receiving the SR also processes the SR received through the PUCCH, and thus assigns a radio resource allocation message to the terminal. When transmitting the transmission delay time, the radio resource allocation message is transmitted through the radio terminal. Therefore, after the SR transmission, there is a minimum time it takes for the terminal to receive the radio resource allocation message, and even in the second section, the terminal generally monitors the downlink channel, which is the same as the first section. Since the terminal is not a section in which the radio resource allocation information can be received from the base station, the terminal can be considered as a section for unnecessarily monitoring the downlink channel.

The third section is a section in which the terminal receives its own radio resource allocation information from the base station from the time when the terminal first receives the UL grant (radio resource allocation information) from the base station. That is, the terminal transmits the radio resource allocation message necessary for the terminal after the base station successfully restores the previously transmitted SR. Therefore, the terminal must receive the downlink channel during the third period.

The fourth section is a period from the time point at which the radio resource allocation information is received until the next SR transmission (when the previous SR transmission fails) on the PUCCH. That is, if the SR transmitted by the terminal is not properly delivered to the base station, the terminal may not receive a radio resource allocation message, and the fourth section occurring in this situation may also receive a downlink channel. Is a waste.

As described above, the operation of continuously monitoring the downlink channel by the terminal in the process of allocating radio resources by the terminal is unnecessary in a specific section. That is, it is inefficient for the terminal to continuously monitor the downlink channel.

Therefore, in the present invention, when the terminal requests the allocation of radio resources to the base station, it is to propose a method for maximizing the power efficiency.

To this end, the present invention proposes that the terminal adjusts the monitoring time of the downlink channel using a timer.

Preferably, after the UE transmits the SR through the PUCCH, the UE operates a sleep mode timer and immediately operates in a continuous reception mode. When the sleep mode timer expires, the terminal stops the continuous reception mode and transitions to the discontinuous reception mode. If the terminal receives radio resource allocation from the base station while the sleep mode timer is in operation, the terminal stops the sleep mode timer.

Preferably, after transmitting the SR through the PUCCH, the UE operates a sleep stop timer, enters a discontinuous reception mode, or stops monitoring downlink channels such as the PDCCH. When the reception stop timer expires, the terminal changes to continuous reception mode and continuously monitors a downlink channel such as the PDCCH. In the above process, additionally, when the reception stop timer expires, the terminal operates the sleep mode timer. When the sleep mode timer expires, the terminal stops the continuous reception mode and transitions to the discontinuous reception mode. If the terminal receives radio resource allocation from the base station while the sleep mode timer is in operation, the terminal stops the sleep mode timer.

Preferably, after the terminal requests allocation of radio resources through a dedicated-scheduling request (D-SR) channel, if the terminal is in the first discontinuous reception mode (Long DRX), the second discontinuous reception mode ( Short DRX).

In the above process, the setting value of the timer may inform the terminal by the base station. In addition, the setting value of the reception stop timer may be set to Round Trip Time (RTT) of HARQ operation.

Therefore, in the present invention, if a certain condition is satisfied after the SR is triggered, the terminal receives the downlink channel. In addition, the present invention proposes that the terminal does not receive (monitor) the downlink channel, except in the case where the terminal needs to receive the downlink channel according to another condition before the predetermined condition is satisfied. Here, the predetermined condition may mean a case in which the terminal transmits an SR through the PUCCH and the SR transmission is in progress.

6 is an exemplary diagram illustrating a process in which a terminal is allocated a radio resource after a scheduling request (SR) is triggered by triggering a buffer status report (BSR) according to the present invention.

As shown in FIG. 6, the process in which the terminal allocates the radio resource may be divided into a total of four sections.

The first section is a period from when a scheduling request (SR) is triggered to when a scheduling request (SR) is first transmitted on a physical uplink control channel (PUCCH). In FIG. 6, it is assumed that the PUCCH resources are allocated to 0ms, 20ms, and 40ms. If the SR is triggered near 2ms, it is 20ms that the actual SR is transmitted through the PUCCH. As described above, in the present invention, if the terminal transmits the SR through the PUCCH, and the SR transmission is in progress, the terminal has proposed not to monitor the downlink channel. Therefore, in the present invention, the terminal does not receive (monitor) the downlink channel in the first section.

The second section is a section from after the SR is transmitted on the PUCCH to a time point where the terminal can first receive a UL Grant from a base station (for example, an eNB). In general, the second section is associated with an up / down round trip time (RTT) and a minimum processing time of the base station. That is, when the SR is actually transmitted through the PUCCH, it is transmitted to the radio end, so a delay occurs, and the base station receiving the SR also processes the SR received through the PUCCH, and thus assigns a radio resource allocation message to the terminal. When transmitting the transmission delay time, the radio resource allocation message is transmitted through the radio terminal. Therefore, after the SR transmission, there is a minimum time until the terminal receives the radio resource allocation message. In the present invention, since the terminal does not receive the downlink channel in the process of receiving the radio resource, except that the terminal must receive the downlink channel by another condition before a certain condition is satisfied, the terminal does not receive the downlink channel. In the second section, the downlink channel may not be monitored.

The third section is a section in which the terminal receives its own radio resource allocation information from the base station from the time when the terminal first receives the UL grant (radio resource allocation information) from the base station. That is, the terminal transmits the radio resource allocation message necessary for the terminal after the base station successfully restores the previously transmitted SR. Therefore, in the present invention, the terminal receives the downlink channel during the third section.

The fourth section is a period from the time point at which the radio resource allocation information is received until the next SR transmission (when the previous SR transmission fails) on the PUCCH. That is, if the SR transmitted by the terminal is not properly delivered to the base station, the terminal cannot receive a radio resource allocation message. In the present invention, since the terminal does not receive the downlink channel in the process of receiving the radio resource, except that the terminal must receive the downlink channel by another condition before a certain condition is satisfied, the terminal does not receive the downlink channel. In section 4, the downlink channel may not be monitored.

As described above, the present invention excludes unnecessary operation of continuously monitoring the downlink channel by the terminal in the process of allocating a radio resource, thus enabling a more efficient radio resource allocation process.

Hereinafter, a terminal according to the present invention will be described.

The terminal according to the present invention includes all types of terminals that can use a service that can exchange data with each other over the air. That is, the terminal according to the present invention is a mobile communication terminal capable of using a wireless communication service (for example, user equipment (UE), mobile phone, cellular phone, DMB phone, DVB-H phone, PDA phone, and PTT phone, etc.) It is a comprehensive meaning including laptops, laptops, laptops, digital TVs, GPS navigation, handheld game consoles, MP3s, and other consumer electronics.

The terminal according to the present invention may include a basic hardware configuration (transmitter / receiver, processor or controller, storage, etc.) required to perform functions and operations for efficient system information reception illustrated in the present invention.

The method according to the invention described thus far can be implemented in software, hardware, or a combination thereof. For example, the method according to the present invention may be stored in a storage medium (eg, internal memory of a mobile terminal or base station, flash memory, hard disk, etc.), and may be stored in a processor (eg, mobile terminal or base station). Code or instructions within a software program that can be executed by an internal microprocessor).

In the above, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (7)

A method of controlling a monitoring operation of a physical downlink channel in a wireless communication system,
Triggering signaling for allocating at least one radio resource for uplink data transmission, the signaling being a scheduling request (SR) signaling;
Determining whether the triggered scheduling request (SR) signaling has been sent to a network; And
Selectively performing the monitoring operation of the physical downlink channel based on the determining step, wherein the monitoring operation is performed if it is determined that the triggered scheduling request (SR) signaling is transmitted to the network. A method for controlling a monitoring operation of a physical downlink channel in a wireless communication system, characterized by the above-mentioned. delete 2. The method of claim 1, wherein if it is determined that the triggered scheduling request (SR) signaling is not transmitted to the network, the monitoring operation is not performed. . 2. The method of claim 1, wherein the scheduling request (SR) signaling is transmitted to a network through a physical uplink control channel (PUCCH). . delete The method of claim 1, wherein the physical downlink channel is a physical downlink control channel (PDCCH). 2. The method of claim 1, wherein said scheduling request (SR) signaling is associated with a scheduling request procedure (SR procedure).

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